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ABSTRACT A comprehensive review of a full developmental sequence of eodiscinid trilobites reported in recent decades from Cambrian Series 2 and 3 strata is presented. These mostly articulated specimens exhibit detailed morphologies with preservation of even delicate structures at different growth stages, such as the bacculae, axial pores, spine pores, pygidial marginal spines and line coaptative structures. Their trunk segmentation schedules displayed a consistent developmental mode in segment generation and liberation, that is tagmosis and somitogenesis occurred heterochronously after each moulting event, providing clues regarding the potential developmental strategy in isopygous and even macropygous trilobites. The fact that the rate of segmentation obviously exceeds that of articulation results in a seemingly prolonged process of the formation of thoracic segments, which might explain why eodiscinid trilobites have a fixed and limited number of thoracic segments. In addition, the relationship between enrollment mechanism and trunk segmentation during eodiscinid ontogeny confirms this highly unusual growth pattern among the Trilobita, revealing why these early‐diverging trilobites controlled the rate of segment increase and release during their life cycles, and is thus of interest with regard to the evolution of arthropod body patterning. [ABSTRACT FROM AUTHOR]

Insectivorous predators, including birds and bats, play crucial roles in trophic cascades. However, previous research on these cascades has often relied on permanent predator exclosures, which prevent the isolation of specific effects of birds and bats, given their different activity patterns throughout the day. Moreover, limited knowledge exists regarding the variations in individual effects of these predators under different biotic and abiotic conditions, such as changes in elevation. To address these uncertainties, our study aimed to investigate the distinct effects of bats and birds on arthropod densities in foliage and herbivory damage in lowland and highland rainforests of Papua New Guinea (PNG). Predator exclosures were established for one month to exclude diurnal or nocturnal predators across 120 saplings (ca. 2.5–4 m tall) selected from two lowland and two highland forests (i.e., 30 saplings per study site) along the Mt. Wilhelm transect in PNG. Arthropods were collected and measured, and herbivory damage was analyzed at the end of the experiment. Birds significantly reduced arthropod densities by 30%, particularly in arthropods longer than 10 mm, regardless of elevation. Additionally, both birds and bats appeared to mitigate herbivory damage in highland forests, with protected saplings displaying up to 189% more herbivory. Our results support previous studies that have demonstrated the ability of insectivorous predators to reduce leaf damage through the control of arthropods. Furthermore, our approach highlights the importance and necessity of further research on the role of seasons and elevations in trophic cascades. [ABSTRACT FROM AUTHOR]

Aim: Long‐standing theory predicts that the intensity of biotic interactions increases from high to low latitudes. Studies addressing geographic variation in predation on insect prey have often relied on prey models, which lack many characteristics of live prey. Our goals were to explore global latitudinal patterns of predator attack rates on standardised live insect prey and to compare the patterns in predation on live insects with those on plasticine prey models. Location: Global forested areas. Time Period: 2021–2023. Major Taxa: Arthropods, birds. Methods: We measured predation rates in 43 forested locations distributed across five continents from 34.1° S to 69.5° N latitude. At each location, we exposed 20 sets of three bait types, one set per tree. Each set included three live fly larvae (maggots), three live fly puparia and three plasticine models of the puparia. We used glue rings to isolate half of the sets from non‐flying predators. Results: Arthropod attack rates on plasticine prey decreased linearly from low to high latitudes, whereas attack rates on maggots had a U shaped distribution, with the lowest predation rates at temperate latitudes and the highest rates at tropical and boreal latitudes. This difference emerged from intensive predator attacks on live maggots, but not on plasticine models, in boreal sites. Site‐specific attack rates of arthropod predators on live and plasticine prey were not correlated. In contrast, bird attack rates on live maggots and plasticine models were positively correlated, but did not show significant latitudinal changes. Main Conclusions: Latitudinal patterns in predation differ between major groups of predators and between types of prey. Poleward decreases in both arthropod and combined arthropod and bird predation on plasticine models do not mirror patterns of predation on our live prey, the latter likely reflecting real patterns of predation risk better than do patterns of attack on artificial prey. [ABSTRACT FROM AUTHOR]

• Refugia or refuges are a concept that can contribute to an understanding of survival in the Anthropocene at different levels of abstraction. • Urban green spaces are areas where interactions between human and non-human nature can occur. They serve as refuges in the city and can be beneficial for both biodiversity and human well-being. • Over 70 % of the reviewed studies report positive effects of unmown refuges on arthropod abundance and richness in meadows or green spaces. • Unmown refuges allow habitat heterogeneity, a shelter for surviving arthropods from mowing, a chance for larval development, and a place to hibernate. Large refugia and small refuges have always been crucial for species survival, particularly during periods like the Ice Age. When their original habitats became uninhabitable, they provided important shelters in space and time. Drawing from a biological and philosophical perspective, we propose creating and preserving refuges as socio-ecological solutions in an epoch primarily shaped by human activity, the Anthropocene. Our focus lies on green refuges within urban settings, given that urbanization is one of the large drivers of insect decline and has adverse effects on humans, such as increased heat. Refuges can be beneficial for both biodiversity and human well-being. After clarifying the relevant terminology on four levels of abstraction, we conducted a systematic biological literature review - as a case study. Here, we summarize the current state of research on the effects of unmown refuges on insects and spiders. The mere existence of refuges proved beneficial for arthropods, with over 70 % of studies reporting positive responses among these species. While insects and spiders have specific habitat requirements, humans are able to create a habitable environment for themselves. However, ecological crises for humans and arthropods are increasing, as are human populations. Therefore, refuges offer a way to address both ecological and social challenges simultaneously, enhancing biodiversity and human well-being. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction: Since its introduction about a decade ago, target enrichment sequencing of ultraconserved elements (UCEs) has proven to be an invaluable tool for studies across evolutionary scales, and thus employed from population genetics, to historical biogeography as well as deep-time phylogenetics. Here, we present the first probe set targeting UCEs in crustaceans, specifically designed for decapods and tested beyond decapods in other malacostracan lineages. Methods: Probes were designed using published genomes of nine decapod and one peracarid species, as well as raw Nanopore long reads of one additional brachyuran species. The final probe set consists of about 20,000 probes, targeting 1,384 unique UCE loci. We compiled a dataset across Malacostraca,as well as datasets of a deep-sea squat lobster genus, and an intertidal mangrove crab species, to test the probe set at different phylogenetic levels (i.e., class, order, genus, within species). Results: Final mean UCE recovery from fresh samples across Malacostraca was 568 loci,with up to 847 and 658 loci recovered from decapod and non-decapod species, respectively. Final mean recovery from fresh samples in the genus- and within species-level datasets was 849 and 787 loci, respectively. Up to several hundreds of UCEs were recovered from historicalmuseum specimens (10 to > 150 years old), that were included in all datasets. UCE-based phylogenies largely reflected the known relationships of the included taxa, and we were able to infer population differentiation based on >600 SNPs extracted from the species-level dataset. Discussion: Our results showcase the versatility of this UCE probe set, yielding informative data from phylogenetic as well as population-genetic datasets. They demonstrate once more that UCEs are a promising technique for leveraging museum specimens for genomic studies, and overall highlight the probe set's potential for crustacean evolutionary studies. [ABSTRACT FROM AUTHOR]

Natural history collections are invaluable reference collections. Digitizing these collections is a transformative process that improves the accessibility, preservation, and exploitation of specimens and associated data in the long term. Arthropods make up the majority of zoological collections. However, arthropods are small, have detailed color textures and share small, complex and shiny structures, which poses a challenge to conventional digitization methods. Sphaeroptica is a multi-images viewer that uses a sphere of oriented images. It allows the visualization of insects including their tiniest features, the positioning of landmarks, and the extraction of 3D coordinates for measuring linear distances or for use in geometric morphometrics analysis. The quantitative comparisons show that the measures obtained with Sphaeroptica are similar to the measurements derived from 3D μCT models with an average difference inferior to 1%, while featuring the high resolution of color stacked pictures with all details like setae, chaetae, scales, and other small and/or complex structures. Shaeroptica was developed for the digitization of small arthropods but it can be used with any sphere of aligned images resulting from the digitization of objects or specimens with complex surface and shining, black, or translucent texture which cannot easily be digitized using structured light scanner or Structure-from-Motion (SfM) photogrammetry. [ABSTRACT FROM AUTHOR]

The Carboniferous myriapod Arthropleura is the largest arthropod of all time, but its fossils are usually incomplete, limiting the understanding of its anatomy, ecology, and relationships. Micro-computed tomography applied to exceptionally preserved specimens from the Carboniferous Montceau-les-Mines Lagerstätte (France) reveals unprecedented details of its functional anatomy, such as the head and mouthparts. Arthropleura shares features with both millipedes and centipedes. Total-evidence phylogeny combining morphological and transcriptomic data resolves Arthropleura alone as a stem group millipede, but the inclusion of the highly incomplete Siluro-Devonian Eoarthropleura draws it deeper into the myriapod stem. Arthropleura suggests transitional morphology between clades united primarily by molecular information and underscores the value of total-evidence phylogenetics to understanding evolutionary history. [ABSTRACT FROM AUTHOR]

The results of faecal analysis in the present study indicated no significant difference in prey items and prey occurrence between breeding and non-breeding seasons in yellow-wattled lapwings. However, Coleoptera and Araneae represented the highest and lowest prey items and prey occurrences respectively. Prey abundance significantly varied between breeding and non-breeding seasons. Uncultivated and cultivated habitat types had the highest and lowest prey abundances respectively. Jacob's index reflected that they primarily consumed arthropod larvae. Additionally, there was a positive selection for adult insects in the orders Coleoptera, Diptera and Blattodea and a negative selection for Oligochaeta, Diplopoda and Araneae. Thus, the yellow-wattled lapwings are flexible feeders, particularly in the breeding season; however, they favour uncultivated areas where food is abundant. [ABSTRACT FROM AUTHOR]

Iron Formations (IF) are threatened by mining, particularly the Mesovoid Shallow Substratum (MSS), an understudied subterranean environment. We evaluate the spatiotemporal patterns of subterranean fauna in MSS of iron duricrust (canga) in the Iron Quadrangle and Southern Espinhaço Range, southeastern Brazil. Samplings took place between July 2014 and June 2022 using five trap types. We sampled 108,005 individuals, 1,054 morphospecies, and seven phyla, globally the largest dataset on MSS in IF. Arthropoda represented 97% of all invertebrates sampled. We identified 31 troglomorphic organisms, primarily Arthropoda and Platyhelminthes. MSS traps were the most efficient method, capturing 80% of all invertebrates. Morphospecies were more prevalent in each locality than shared among localities. Species replacement was the main processes to spatial differences. Over time, we found a decrease of total dissimilarity and importance of species replacement for troglomorphic organisms. A positive correlation between spatial distance and compositional dissimilarity of invertebrates was found. Iron Quadrangle and Southern Espinhaço Range showed marked differences in the spatiotemporal patterns of subterranean fauna. Brazilian IF are threatened, with their biological significance not fully understood but highly endangered due their limited distribution. Conservation efforts require a comprehensive understanding of both biotic and abiotic factors shaping the entire IF ecosystem. [ABSTRACT FROM AUTHOR]

We are far from knowing all species living on the planet. Understanding biodiversity is demanding and requires time and expertise. Most groups are understudied given problems of identifying and delimiting species. DNA barcoding emerged to overcome some of the difficulties in identifying species. Its limitations derive from incomplete taxonomic knowledge and the lack of comprehensive DNA barcode libraries for so many taxonomic groups. Here, we evaluate how useful barcoding is for identifying arthropods from highly diverse leaf litter communities in the southern Appalachian Mountains (USA). We used 3 reference databases and several automated classification methods on a data set including several arthropod groups. Acari, Araneae, Collembola, Coleoptera, Diptera, and Hymenoptera were well represented, showing different performances across methods and databases. Spiders performed the best, with correct identification rates to species and genus levels of ~50% across databases. Springtails performed poorly, no barcodes were identified to species or genus. Other groups showed poor to mediocre performance, from around 3% (mites) to 20% (beetles) correctly identified barcodes to species, but also with some false identifications. In general, BOLD-based identification offered the best identification results but, in all cases except spiders, performance is poor, with less than a fifth of specimens correctly identified to genus or species. Our results indicate that the soil arthropod fauna is still insufficiently documented, with many species unrepresented in DNA barcode libraries. More effort toward integrative taxonomic characterization is needed to complete our reference libraries before we can rely on DNA barcoding as a universally applicable identification method. [ABSTRACT FROM AUTHOR]

The performance of herbivorous animals depends on the nutritional and defensive traits of the plants they consume. The uptake and deposition of biogenic silicon in plant tissues is arguably the most basic and ubiquitous anti‐herbivore defence used by plants, especially grasses. We conducted meta‐analyses of 150 studies reporting how vertebrate and invertebrate herbivores performed when feeding on silicon‐rich plants relative to those feeding on low‐silicon plants. Silicon levels were 52% higher and 32% more variable in silicon‐rich plants compared to plants with low silicon, which resulted in an overall 33% decline in herbivore performance. Fluid‐feeding herbivore performance was less adversely impacted (−14%) than tissue‐chewing herbivores, including mammals (−45%), chewing arthropods (−33%) and plant‐boring arthropods (−39%). Fluid‐feeding arthropods with a wide diet breadth or those feeding on perennial plant species were mostly unaffected by silicon defences. Unlike many other plant defences, where diet specialisation often helps herbivores overcome their effects, silicon negatively impacts chewing herbivores regardless of diet breadth. We conclude that silicon defences primarily target chewing herbivores and impact vertebrate and invertebrate herbivores to a similar degree. [ABSTRACT FROM AUTHOR]

Coastal grasslands host diverse arthropod communities and provide important ecosystem services. Islands, being isolated environments, are expected to have simpler ecosystems than continental areas, with the few successful colonizing species often attaining high densities; however, these patterns are still poorly documented for coastal grassland arthropods. We conducted a comparative study of the biodiversity of arthropod communities in two distinct coastal grassland ecosystems (Portugal mainland and the Azores) with the following objectives: (a) to investigate the arthropod community composition in both locations; (b) to compare the diversity profiles in both locations; (c) to investigate potential density compensation in the island's arthropod communities. For four months, arthropods were collected on the Island of São Miguel, Setúbal Peninsula, and Sine's region and subsequently classified into taxonomic groups. With the data collected, Hill Numbers were calculated for each region. We confirmed that the richness on the mainland was higher than in the Azores, and we found some apparent abundance compensation in the Azores. At the same time, we also observed that many species in the Azores are also present in the continental coastal grasslands of mainland Portugal. [ABSTRACT FROM AUTHOR]

Larger effective populations (Ne) are characterized by higher genetic diversity, which is expected to predict population performance (average individual performance that influences fitness). Empirical studies of the relationship between neutral diversity and performance mostly represent species with small Ne, while there is limited data from the species-rich and ecologically important arthropods that are assumed to have large Ne but are threatened by massive declines. We performed a systematic literature search and used meta-analytical models to test the prediction of a positive association between neutral genetic diversity and performance in wild arthropods. From 14 relevant studies of 286 populations, we detected a weak (r = 0.15) but nonsignificant positive association both in the full data set (121 effect sizes) and a reduced data set accounting for dependency (14 effect sizes). Theory predicts that traits closely associated with fitness show a relatively stronger correlation with neutral diversity; this relationship was upheld for longevity and marginally for reproduction. Our analyses point to major knowledge gaps in our understanding of relationships between neutral diversity and performance. Future studies using genome-wide data sets across populations could guide more powerful designs to evaluate relationships between adaptive, deleterious and neutral diversity and performance. Graphical Abstract Based on a systematic literature search and meta-analytical models, we tested the prediction of a positive association between neutral genetic diversity and performance in wild arthropod populations and found a weak (r = 0.15) but nonsignificant positive association (121 effect sizes from 286 populations). We propose future use of genome-wide data sets across populations of different Ne for evaluating relationships between adaptive, deleterious, and neutral diversity and performance. [ABSTRACT FROM AUTHOR]

In arthropods, hematophagy has arisen several times throughout evolution. This specialized feeding behavior offered a highly nutritious diet obtained during blood feeds. On the other hand, blood‐sucking arthropods must overcome problems brought on by blood intake and digestion. Host blood complement acts on the bite site and is still active after ingestion, so complement activation is a potential threat to the host's skin feeding environment and to the arthropod gut enterocytes. During evolution, blood‐sucking arthropods have selected, either in their saliva or gut, anticomplement molecules that inactivate host blood complement. This review presents an overview of the complement system and discusses the arthropod's salivary and gut anticomplement molecules studied to date, exploring their mechanism of action and other aspects related to the arthropod–host–pathogen interface. The possible therapeutic applications of arthropod's anticomplement molecules are also discussed. [ABSTRACT FROM AUTHOR]

Background: The sea spiders (Pycnogonida Latreille, 1810) of the Hunsrück Slate (Lower Devonian, ~400 million years ago) are iconic in their abundance, exquisite pyritic preservation, and in their distinctive body plan compared to extant sea spiders (Pantopoda Gerstäcker, 1863). Consequently, the Hunsrück sea spiders are important in understanding the deep evolutionary history of Pycnogonida, yet they remain poorly characterised, impacting upon attempts to establish a time-calibrated phylogeny of sea spiders. Methods: Here, we investigated previously described and new material representing four of the five Hunsrück pycnogonids: Flagellopantopus blocki Poschmann & Dunlop, 2006; Palaeoisopus problematicus Broili, 1928; Palaeopantopus maucheri Broili, 1929; and Pentapantopus vogteli Kühl, Poschmann & Rust, 2013; as well as a few unidentified specimens. Using X-ray microtomography and Reflectance Transformation Imaging, we describe new fossils, provide evidence for newly revealed anatomical features, and interpret these data in comparison to extant species. We also reinterpret the previously published illustration of the (probably lost) holotype of Palaeothea devonica Bergström, Stürmer & Winter, 1980. Results: We provide the first detailed description of the cephalic appendages of Palaeoisopus problematicus and revise the interpretation of the organisation of its ocular tubercle. Furthermore, we provide new insights into the structure of the legs and the proboscis of Palaeopantopus maucheri, the first description of the body of Flagellopantopus blocki and describe a new specimen of Pentapantopus vogteli, demonstrating that it had eight legs, in contrast to previous interpretations. We argue that, contrary to previous suggestions, Palaeothea devonica probably had a different body plan from extant pantopods. We discuss the ecological traits of the Hunsrück pycnogonids based on their morphological adaptations, and conclude that there is no compelling evidence of Pantopoda in the Devonian. Through comparative interpretation of the legs as well as general morphology, we can divide the Hunsrück pycnogonids into two morphological groups, while Pantopoda constitutes a third morphological group. [ABSTRACT FROM AUTHOR]

Background: Spiders evolved different types of eyes, a pair of primary eyes that are usually forward pointing, and three pairs of secondary eyes that are typically situated more posterior and lateral on the spider's head. The best understanding of arthropod eye development comes from the vinegar fly Drosophila melanogaster, the main arthropod model organism, that also evolved different types of eyes, the larval eyes and the ocelli and compound eyes of the imago. The gene regulatory networks that underlie eye development in this species are well investigated revealing a conserved core network, but also show several differences between the different types of eyes. Recent candidate gene approaches identified a number of conserved genes in arthropod eye development, but also revealed crucial differences including the apparent lack of some key factors in some groups of arthropods, including spiders. Results: Here, we re-analysed our published scRNA sequencing data and found potential key regulators of spider eye development that were previously overlooked. Unlike earlier research on this topic, our new data suggest that Hedgehog (Hh)-signalling is involved in eye development in the spider Parasteatoda tepidariorum. By investigating embryonic gene expression in representatives of all main groups of spiders, we demonstrate that this involvement is conserved in spiders. Additionally, we identified genes that are expressed in the developing eyes of spiders, but that have not been studied in this context before. Conclusion: Our data show that single-cell sequencing represents a powerful method to gain deeper insight into gene regulatory networks that underlie the development of lineage-specific organs such as the derived set of eyes in spiders. Overall, we gained deeper insight into spider eye development, as well as the evolution of arthropod visual system formation. [ABSTRACT FROM AUTHOR]

Background: Regenerating legs is advantageous for arthropods as their appendages exhibit crucial functional specializations. Many arthropods possess a 'preferred breakage point', where the appendage is most likely to break and where regeneration likely to occur, however, different taxa exhibit different levels of regenerative potential. Centipede appendage regeneration is categorized as 'progressive' or 'explosive'. In the later, the appendage is fully regenerated after one molt. This term was used for house centipedes that frequently lose their long legs. We chose Scutigera coleoptrata as a model to comprehensively investigate the process of leg appendotomy and regeneration as well as compare it with leg development in anamorphic instars. Results: The trochanter exhibits a preferred breakage point. Internally, it houses a three-layered diaphragm that effectively seals the lumen. In case of leg loss, the wound is quickly sealed. The epidermis detaches from the cuticle and muscles of the coxa get compacted, giving sufficient space for the regenerating leg. A blastema forms and the leg then grows in a coiled manner. The regenerating leg is innervated and syncytial muscles form. If the leg is lost in an early intermolt phase, progression of regeneration is slower than when a specimen is closer to the next molt. Instars of house centipedes can simultaneously develop and regenerate legs. The legs develop laterally on the posterior segments under the cuticle. As opposed to regeneration, the progression of leg development always follows the same temporal pattern throughout the entire intermolt phase. Conclusion: Several factors are of major significance in house centipede leg regeneration. First, the ease with which they lose legs: the diaphragm represents an efficient tool for appendotomy. Moreover, the functional extension of the coxa provides space for a leg to be regenerated in. Lastly, the genetic predisposition allows them to regenerate legs within one molting cycle. This "package" is unique among land arthropods, and to this degree rare in marine taxa. Furthermore, observing leg regeneration and anamorphic leg development in parallel suggest that regeneration is most likely an epiphenomenon of development, and the differences are a requirement for the novel context in which re-development occurs. [ABSTRACT FROM AUTHOR]

Our understanding of the spread of yeasts in natural ecosystems remains somewhat limited. The recent momentum of yeast ecology research has unveiled novel habitats and vectors that, alongside human activities, impact yeast communities in their natural environments. Yeasts, as non-airborne microorganisms, rely on animal vectors, predominantly insects. However, the overlooked actor in this interplay is the environmental matrix, a player potentially influencing yeast populations and their vectors. This study aims to delve deeper into the intricate, multi-layered connections between yeast populations and ecosystems, focusing on the interactions between the attributes of the environmental matrix, arthropod diversity, and the mycobiota within a renowned yeast-inhabited framework: the vineyard. To investigate these relationships, we sampled both invertebrate and yeast diversity in six organic and conventional vineyards described in terms of management and landscape composition. We identified 80 different invertebrate taxa and isolated 170 yeast strains belonging to 18 species. Notably, new species-specific yeast-insect associations were observed, including the exclusive association between Candida orthopsilosis and Hymenoptera and between Metschnikowia pulcherrima and Coleoptera. These newly identified potential associations provide valuable insights into insect and yeast physiology, hence holding the promise of enhancing our understanding of yeast and arthropod ecology and their collective impact on overall ecosystem health. [ABSTRACT FROM AUTHOR]

Multi‐decadal monitoring has revealed dramatic evidence of global decline in arthropod biomass and biodiversity, yet little baseline information exists for Alaska, a region 1/5th the size of the contiguous US states.We documented patterns of aerial arthropod biomass and diversity in a multi‐year investigation of three regions in boreal Alaska—two in central Alaska (Fairbanks and Tetlin) and one in southcentral Alaska (Anchorage). Sampling employed canopy Malaise and near‐ground pollinator traps as part of a parallel study of a steeply declining songbird. Traps yielded 115,078 specimens of 15 orders and 692 unique taxa with body sizes ≥3 mm.During peak summer (15 June–15 July), mean aerial arthropod biomass was more than three times higher in traps in Fairbanks (50.6 mg·d−1, confidence interval [CI]: 34.5–63.7) than Anchorage (15.8 mg·d−1, CI: 9.3–26.4). Tetlin exhibited an intermediate value (35.4 mg·d−1, CI: 18.4–67.4). Temperature correlated positively with captured biomass, whereas wind (above 1.5 m·s−1) correlated negatively.To obtain species‐level diversity data, we focused on beetles, representing a wide range of feeding guilds and taxa. Beetles accounted for 6229 adult specimens, 364 unique (mostly species‐level) taxa and 47 families. Trophic categorizations of beetles were similar for the central Alaskan sites; both had a greater proportion of wood‐feeding beetles than Anchorage. Ten species are potentially new to science and 49 are new state records for Alaska.Our work provides the first insight into regional differences and seasonal trends in aerial arthropod biomass and diversity in boreal Alaska, creating important baselines for the future. [ABSTRACT FROM AUTHOR]

Head segments play a critical role in revealing the relationships within major arthropod groups but the accurate determination of their number and relationship is challenging because of the decoupling of dorsal tergites and ventral appendages. In recent decades, trilobites have been considered to have four pairs of cephalic appendages and, commonly, five dorsal segments, which has served as the basis for understanding euarthropod cephalic evolution. Based on multiple analytical techniques applied to well‐preserved soft‐bodied specimens of the Upper Ordovician olenid Triarthrus eatoni and middle Cambrian corynexochid Olenoides serratus, we argue that an additional pair of cephalic biramous appendages occurred just behind the antennae, indicating that trilobites had five pairs of cephalic appendages and six dorsally expressed segments. We propose that the mismatch between the four dorsal furrows and five ventral appendages in Olenoides may be reconciled by considering the morphology of the hypostome that marks the position of the antenna and the bifurcation of the first glabellar furrow that has two muscle attachment sites fused. The fusion of clustered attachment sites of the cephalic biramous appendages may have aided feeding ability by gathering the limb bases close to the mouth. [ABSTRACT FROM AUTHOR]

The Pinus palustris (Longleaf Pine) ecosystem contains a diverse array of arthropods, yet the composition of the arthropod community of the canopy layer is largely unknown. We surveyed canopy arthropods using flight-intercept traps placed in the mid-canopy of Longleaf Pine trees at the Jones Center at Ichauway to determine which taxa inhabit the canopies, and assess abundance and richness among 3 ecological communities. We collected a total of 4004 arthropods from May to August 2022. Diptera, Collembola, and Lepidoptera were the most abundant orders. Overall, order- and family-level abundance and order-level richness were similar among ecological communities. However, hemipteran family-level richness differed significantly among the ecological communities. This preliminary research lays the foundation for further canopy arthropod research in endangered Longleaf Pine ecosystems. [ABSTRACT FROM AUTHOR]

Simple Summary: In China, in addition to green tides and red tides, outbreaks of Cnidaria (jellyfish organisms), Annelida (Urechis unicinctus Drasche, 1880), Mollusca (Philine kinglipini S. Tchang, 1934), Arthropoda (Acetes chinensis Hansen, 1919), and Echinodermata (Asteroidea organisms (commonly known as starfish), Ophiuroidea organisms, and Acaudina molpadioides Semper, 1867) not only damage marine resources, tourism, coastal industries, and navigation but also profoundly impact ecosystems near nuclear plants, beaches, and infrastructures, endangering human lives. This article suggests measures to mitigate future disasters, emphasizing enhanced monitoring and integration into China's marine ecological disaster monitoring system. This review is conducive to enhancing researchers' comprehension and reflection regarding biological disasters in marine ecosystems. Owing to global climate change or the ever-more frequent human activities in the offshore areas, it is highly probable that an imbalance in the offshore ecosystem has been induced. However, the importance of maintaining and protecting marine ecosystems' balance cannot be overstated. In recent years, various marine disasters have occurred frequently, such as harmful algal blooms (green tides and red tides), storm surge disasters, wave disasters, sea ice disasters, and tsunami disasters. Additionally, overpopulation of certain marine organisms (particularly marine faunas) has led to marine disasters, threatening both marine ecosystems and human safety. The marine ecological disaster monitoring system in China primarily focuses on monitoring and controlling the outbreak of green tides (mainly caused by outbreaks of some Ulva species) and red tides (mainly caused by outbreaks of some diatom and dinoflagellate species). Currently, there are outbreaks of Cnidaria (Hydrozoa and Scyphozoa organisms; outbreak species are frequently referred to as jellyfish), Annelida (Urechis unicinctus Drasche, 1880), Mollusca (Philine kinglipini S. Tchang, 1934), Arthropoda (Acetes chinensis Hansen, 1919), and Echinodermata (Asteroidea organisms, Ophiuroidea organisms, and Acaudina molpadioides Semper, 1867) in China. They not only cause significant damage to marine fisheries, tourism, coastal industries, and ship navigation but also have profound impacts on marine ecosystems, especially near nuclear power plants, sea bathing beaches, and infrastructures, posing threats to human lives. Therefore, this review provides a detailed introduction to the marine organisms (especially marine fauna species) causing marine biological disasters in China, the current outbreak situations, and the biological backgrounds of these outbreaks. This review also provides an analysis of the causes of these outbreaks. Furthermore, it presents future prospects for marine biological disasters, proposing corresponding measures and advocating for enhanced resource utilization and fundamental research. It is recommended that future efforts focus on improving the monitoring of marine biological disasters and integrating them into the marine ecological disaster monitoring system. The aim of this review is to offer reference information and constructive suggestions for enhancing future monitoring, early warning systems, and prevention efforts related to marine ecological disasters in support of the healthy development and stable operation of marine ecosystems. [ABSTRACT FROM AUTHOR]

Arthropoda represents the most diverse animal phylum, but clarifying the phylogenetic relationships among arthropod taxa remains challenging given the numerous arthropod lineages that diverged over a short period of time. In order to resolve the most controversial aspects of deep arthropod phylogeny, focusing on the Myriapoda, we conducted phylogenetic analyses based on ten super-matrices comprised of 751 to 1,233 orthologous genes across 64 representative arthropod species, including 28 transcriptomes that were newly generated in this study. Our findings provide unambiguous support for the monophyly of the higher arthropod taxa, Chelicerata, Mandibulata, Myriapoda, Pancrustacea, and Hexapoda, while the Crustacea are paraphyletic, with the class Remipedia supported as the lineage most closely related to hexapods. Within the Hexapoda, our results largely affirm previously proposed phylogenetic relationships among deep hexapod lineages, except that the Paraneoptera (Hemiptera, Thysanoptera, and Psocodea) was recovered as a monophyletic lineage in some analyses. The results corroborated the recently proposed phylogenetic framework of the four myriapod classes, wherein Symphyla and Pauropoda, as well as Chilopoda and Diplopoda, are each proposed to be sister taxa. The findings provide important insights into understanding the phylogeny and evolution of arthropods. [ABSTRACT FROM AUTHOR]

Recent metagenomic studies have identified numerous lineages of hydrogen-dependent, obligately methyl-reducing methanogens. Yet, only a few representatives have been isolated in pure culture. Here, we describe six new species with this capability in the family Methanosarcinaceae (order Methanosarcinales), which makes up a substantial fraction of the methanogenic community in arthropod guts. Phylogenomic analysis placed the isolates from cockroach hindguts into the genus Methanimicrococcus (M. hacksteinii, M. hongohii , and M. stummii) and the isolates from millipede hindguts into a new genus, Methanolapillus (M. africanus, M. millepedarum , and M. ohkumae). Members of this intestinal clade, which includes also uncultured representatives from termites and vertebrates, have substantially smaller genomes (1.6–2.2 Mbp) than other Methanosarcinales. Genome reduction was accompanied by the loss of the upper part of the Wood–Ljungdahl pathway, several energy-converting membrane complexes (Fpo, Ech, and Rnf), and various biosynthetic pathways. However, genes involved in the protection against reactive oxygen species (catalase and superoxide reductase) were conserved in all genomes, including cytochrome bd (CydAB), a high-affinity terminal oxidase that may confer the capacity for microaerobic respiration. Since host-associated Methanosarcinales are nested within omnivorous lineages, we conclude that the specialization on methyl groups is an adaptation to the intestinal environment. [ABSTRACT FROM AUTHOR]

We examined the feeding habits and seasonal changes in invasive masked palm civets (Paguma larvata) in northern Japan, to understand their feeding strategies. Between 2020 and 2022, we collected 98 fecal samples from masked palm civets and analyzed their content. The civets fed mainly on fruits (78 % in terms of the point-frame method) and arthropods (15 %); fruits were consumed throughout the year, but increased in winter when arthropods were not available. The feeding plasticity of masked palm civets, in addition to their physical and behavioral adaptations, enables them to expand their distribution in introduced habitats in temperate regions. [ABSTRACT FROM AUTHOR]

Arthropods play vital roles in ecosystem functions, yet their distribution is subjected to environmental factors. Hence, this study investigates the impact of habitat features on arthropod communities within cocoa smallholdings under different farming practices: agroforestry and monoculture systems. We conducted arthropod sampling using yellow sticky traps and assessed the habitat features at each plantation twice to capture temporal variations in arthropod populations. The study recorded 2945 individual arthropods belonging to eight different functional groups. The most abundant functional group was saprophagous, followed by phytophagous, parasitoid, predator, mycetophagous, frugivorous, palynivore, and nectarivorous group. Using Generalized Linear Mixed Models (GLMMs), we found that the abundance of phytophagous and predatory arthropods increases with leaf litter, while it decreases with saprophagous arthropods. Our findings suggest that tree-crop diversification within cocoa smallholdings can play a significant role in preserving higher arthropod biodiversity, particularly when these smallholdings remain free from chemical insecticide use. Canopy cover was also found to positively affect the variability of arthropods indicating that it is a crucial factor affecting arthropod biodiversity. This study underscores the significance of integrating agroforestry systems into cocoa production landscapes, particularly those utilizing agrochemicals, to support diverse arthropod communities and promote sustainable cocoa production. [ABSTRACT FROM AUTHOR]

The attractive effect of dung on coprophagous beetle communities and their role in dung degradation are well‐known phenomena. However, little research has been conducted on the recruitment capacity of this substrate for other arthropods, especially those inhabiting the soil. With the aim of beginning to recognize general patterns in these relationships, the influence of the structure and origin of dung from invasive exotic mammals on the recruitment of microarthropods was investigated in two meadows within Nahuel Huapi National Park in southwestern Argentina. Abundance, richness and diversity of microarthropod communities collected on invasive mammal dung were studied. A total of 2478 microarthropods were collected and 52 species were identified. Recruitment of microarthropods on dung of two invasive coprophagic herbivores, the rabbit, Oryctolagus cuniculus and the hare, Lepus europaeus, were compared with two invasive non‐coprophagic mammals, one herbivorous, the red deer, Cervus elaphus and one omnivorous, the wild boar, Sus scrofa. Pellets of S. scrofa showed the highest microarthropod abundance and richness while diversity was greatest on pellets of C. elaphus. Pygmephorid and oribatid mites and springtails were the most abundant. Liposcelis psocopterans and oribatid mites were more abundant on S. scrofa dung. Low similarity was observed when comparing dung of invasive mammals from different sites revealing spatial variability regarding species composition. Based on its more diverse diet, we conclude that S. scrofa dung exerts a strong influence on microarthropod communities by recruiting a greater number of individuals and species than the dung of the remaining invasive mammals. [ABSTRACT FROM AUTHOR]

The ongoing depletion of the diversity of Pachylinae, the largest subfamily within Gonyleptidae, is progressing. The unranked clade DRMN continues to expand, now incorporating two additional genera – Gyndoides Mello-Leitão, 1927, and Sertaneja Saraiva, Hara & DaSilva, 2021 – previously classified under Pachylinae. Through a cladistic analysis, with an expansion of the morphological dataset used in previous works, our research reveals that both Gyndoides and Sertaneja are separately placed within DRMN. As DRMN is not a formal Linnean taxon, both genera are herein called Gonyleptidae incertae sedis to avoid the establishment of new monogeneric subfamilies. A new species of Gyndoides is described from the state of Paraná, marking the first record for the genus from this state. The other two species, from Santa Catarina state, are herein redescribed, and an emended diagnosis is provided for the genus. [ABSTRACT FROM AUTHOR]

Recent losses in the abundance and diversity of arthropods have been documented in many regions and ecosystems. In grasslands, such insect declines are largely attributed to land use, including modern machinery and mowing regimes. However, the effects of different mowing techniques on arthropods remain poorly understood. Using 11 years of data from 111 agricultural grassland plots across Germany, we analyzed the influence of various grassland management variables on the abundance and abundance‐accounted species richness of four arthropod orders: Araneae, Coleoptera, Hemiptera, and Orthoptera. The analysis focused on detailed mowing information, for example, days after mowing and mower type, and compared their effect with other aspects of grassland management, that is, rolling, leveling, fertilization, and grazing. We found strong negative effects of mowing on all four arthropod orders, with arthropod abundance being lowest directly after mowing and steadily increasing to three to seven times the abundance after 100 days post‐mowing. Likewise, Hemiptera and Coleoptera species richness was 30% higher 100 days after mowing. Mower width showed a positive effect on Orthoptera abundance, but not on the other arthropods. Arthropod abundance and Coleoptera species richness were lowest when a mulcher was used compared to rotary or bar mowers. In addition to mowing, intensive grazing negatively affected Orthoptera abundance but not the other orders. Mowing represents a highly disturbing and iterative stressor with negative effects on arthropod abundance and diversity, likely contributed by mowing‐induced mortality and habitat alteration. While modifications of mowing techniques such as mower type or mowing height and width may help to reduce the negative impact of mowing on arthropods, our results show that mowing itself has the most substantial negative effect. Based on our results, we suggest that reduced mowing frequency, omission of mowing in parts of the grassland (refuges), or extensive grazing instead of mowing have the greatest potential to promote arthropod populations. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether Buthus martensii karsch (Scorpiones), Scolopendra subspinipes mutilans L. Koch (Scolopendra) and Gekko gecko Linnaeus (Gekko) could ameliorate the hypoxic tumor microenvironment and inhibit lung cancer growth and metastasis by regulating phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin/hypoxia-inducible factor-1α (PI3K/AKT/mTOR/HIF-1α) signaling pathway. Methods: Male C57BL/6J mice were inoculated with luciferase labeled LL/2-luc-M38 cell suspension to develop lung cancer models, with rapamycin and cyclophosphamide as positive controls. Carboxy methyl cellulose solutions of Scorpiones, Scolopendra and Gekko were administered intragastrically as 0.33, 0.33, and 0.83 g/kg, respectively once daily for 21 days. Fluorescent expression were detected every 7 days after inoculation, and tumor growth curves were plotted. Immunohistochemistry was performed to determine CD31 and HIF-1α expressions in tumor tissue and microvessel density (MVD) was analyzed. Western blot was performed to detect the expression of PI3K/AKT/mTOR/HIF-1α signaling pathway-related proteins. Enzyme-linked immunosorbent assay was performed to detect serum basic fibroblast growth factor (bFGF), transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF) in mice. Results: Scorpiones, Scolopendra and Gekko prolonged the survival time and inhibited lung cancer metastasis and expression of HIF-1α (all P<0.01). Moreover, Scorpiones, Scolopendra and Gekko inhibited the phosphorylation of AKT and ribosomal protein S6 kinase (p70S6K) (P<0.05 or P<0.01). In addition, they also decreased the expression of CD31, MVD, bFGF, TGF-β1 and VEGF compared with the model group (P<0.05 or P<0.01). Conclusion: Scorpiones, Scolopendra and Gekko all showed beneficial effects on lung cancer by ameliorating the hypoxic tumor microenvironment via PI3K/AKT/mTOR/HIF-1α signaling pathway. [ABSTRACT FROM AUTHOR]

Abstract Background Regenerating legs is advantageous for arthropods as their appendages exhibit crucial functional specializations. Many arthropods possess a ‘preferred breakage point’, where the appendage is most likely to break and where regeneration likely to occur, however, different taxa exhibit different levels of regenerative potential. Centipede appendage regeneration is categorized as 'progressive' or 'explosive'. In the later, the appendage is fully regenerated after one molt. This term was used for house centipedes that frequently lose their long legs. We chose Scutigera coleoptrata as a model to comprehensively investigate the process of leg appendotomy and regeneration as well as compare it with leg development in anamorphic instars. Results The trochanter exhibits a preferred breakage point. Internally, it houses a three-layered diaphragm that effectively seals the lumen. In case of leg loss, the wound is quickly sealed. The epidermis detaches from the cuticle and muscles of the coxa get compacted, giving sufficient space for the regenerating leg. A blastema forms and the leg then grows in a coiled manner. The regenerating leg is innervated and syncytial muscles form. If the leg is lost in an early intermolt phase, progression of regeneration is slower than when a specimen is closer to the next molt. Instars of house centipedes can simultaneously develop and regenerate legs. The legs develop laterally on the posterior segments under the cuticle. As opposed to regeneration, the progression of leg development always follows the same temporal pattern throughout the entire intermolt phase. Conclusion Several factors are of major significance in house centipede leg regeneration. First, the ease with which they lose legs: the diaphragm represents an efficient tool for appendotomy. Moreover, the functional extension of the coxa provides space for a leg to be regenerated in. Lastly, the genetic predisposition allows them to regenerate legs within one molting cycle. This “package” is unique among land arthropods, and to this degree rare in marine taxa. Furthermore, observing leg regeneration and anamorphic leg development in parallel suggest that regeneration is most likely an epiphenomenon of development, and the differences are a requirement for the novel context in which re-development occurs.

Background: Arthropods represent the largest and most diverse phylum on Earth, playing a pivotal role in the biosphere. One key to their evolutionary success is their ability to feed on plant material. However, their endogenous enzymatic repertoire, which contributes to plant digestion, remains largely unexplored and poorly understood. Results: We analyzed 815 arthropod proteomes and identified a total of 268,171 carbohydrate-active modules. Our findings revealed a strong correlation between enzymatic content and feeding habits, with herbivorous species possessing significantly higher enzyme levels. We identified widespread carbohydrate-active families across the AA, CBM, GH, and GT classes, and observed a progressive increase in taxa-exclusive families in more recent arthropod lineages. Notably, we highlighted the impact of the transition from ametabolous to holometabolous development on carbohydrate metabolism, as well as the ecological adaptations of different species groups. By reconstructing the ancestral enzymatic profiles of arthropods, we identified significant fluctuations in 10 carbohydrate-active families over time. Conclusions: Our analysis advances the understanding of the evolutionary mechanisms utilized by the megadiverse phylum Arthropoda. We emphasize the critical role of herbivory as a selective force shaping enzymatic strategies, particularly those involved in carbohydrate metabolism. The distribution and exclusivity of carbohydrate-active families across different arthropod groups provide insights into their evolutionary trajectories and offer a clearer picture of the metabolic pathways that led their ancestors to their present forms.

Exoskeletons are a defining character of all arthropods that provide physical support for their segmented bodies and appendages as well as protection from the environment and predation. This ubiquitous yet evolutionarily variable feature has been instrumental in facilitating the adoption of a variety of lifestyles and the exploitation of ecological niches across all environments. Throughout the radiation that produced the more than one million described modern species, adaptability afforded by segmentation and exoskeletons has led to a diversity that is unrivalled amongst animals. However, because of the limited extensibility of exoskeleton chitin and cuticle components, they must be periodically shed and replaced with new larger ones, notably to accommodate the growing individuals encased within. Therefore, arthropods grow discontinuously by undergoing periodic moulting events, which follow a series of steps from the preparatory pre‐moult phase to ecdysis itself and post‐moult maturation of new exoskeletons. Each event represents a particularly vulnerable period in an arthropod's life cycle, so processes must be tightly regulated and meticulously executed to ensure successful transitions for normal growth and development. Decades of research in representative arthropods provide a foundation of understanding of the mechanisms involved. Building on this, studies continue to develop and test hypotheses on the presence and function of molecular components, including neuropeptides, hormones, and receptors, as well as the so‐called early, late, and fate genes, across arthropod diversity. Here, we review the literature to develop a comprehensive overview of the status of accumulated knowledge of the genetic toolkit governing arthropod moulting. From biosynthesis and regulation of ecdysteroid and sesquiterpenoid hormones, to factors involved in hormonal stimulation responses and exoskeleton remodelling, we identify commonalities and differences, as well as highlighting major knowledge gaps, across arthropod groups. We examine the available evidence supporting current models of how components operate together to prepare for, execute, and recover from ecdysis, comparing reports from Chelicerata, Myriapoda, Crustacea, and Hexapoda. Evidence is generally highly taxonomically imbalanced, with most reports based on insect study systems. Biases are also evident in research on different moulting phases and processes, with the early triggers and late effectors generally being the least well explored. Our synthesis contrasts knowledge based on reported observations with reasonably plausible assumptions given current taxonomic sampling, and exposes weak assumptions or major gaps that need addressing. Encouragingly, advances in genomics are driving a diversification of tractable study systems by facilitating the cataloguing of putative genetic toolkits in previously under‐explored taxa. Analysis of genome and transcriptome data supported by experimental investigations have validated the presence of an "ultra‐conserved" core of arthropod genes involved in moulting processes. The molecular machinery has likely evolved with elaborations on this conserved pathway backbone, but more taxonomic exploration is needed to characterise lineage‐specific changes and novelties. Furthermore, linking these to transformative innovations in moulting processes across Arthropoda remains hampered by knowledge gaps and hypotheses based on untested assumptions. Promisingly however, emerging from the synthesis is a framework that highlights research avenues from the underlying genetics to the dynamic molecular biology through to the complex physiology of moulting. [ABSTRACT FROM AUTHOR]

Gut content metabarcoding has provided important insights into the food web ecology of spiders, the most dominant terrestrial arthropod predators. In small invertebrates, like spiders, gut content analysis is often performed on whole body DNA extracts of individual predators, from which prey sequences are selectively enriched and sequenced.Since many spider species are generalist predators, large numbers of samples comprising individual spider specimens must be analysed to recover an exhaustive image of a spider species' prey spectrum, which is costly and time‐consuming.Pooled processing of bulk samples of multiple specimens has been suggested to reduce the necessary workload and cost while still recovering a representative estimate of the prey diversity. However, it is still unclear if pooling approaches lead to bias in recovering the prey spectrum and if the results are comparable with data from individually processed spiders.Here, we test the effects of metabarcoding pooled spider gut content on the recovered taxonomic diversity and composition of prey. Using a newly adapted primer pair, which efficiently enriches COI barcode sequences of diverse arthropod prey groups while suppressing spider amplification, we test if pooling leads to reduced taxonomic diversity or skewed estimates of prey composition.Our results show that pooling and individual processing recover highly correlated taxonomic diversity and composition of prey. The only exception are very rare prey items which were less well recovered by pooling. Our results support pooling as a cost‐effective and time‐efficient approach to recover the diet of generalist predators for population‐level studies of spider trophic interactions. [ABSTRACT FROM AUTHOR]

Prey-predator interactions are fundamental to ecosystem balance, with predators regulating prey populations. Yet, the degree of this interaction varies, depending on the conditions and structure of the ecosystem. We investigated the influence of leaf herbivory, predator types, and levels of urbanisation on the predation risk of artificial caterpillar prey within an urban-agricultural landscape in southcentral Mindanao, Philippines. Four hundred and seventy-three (31.53%) of the 1500 artificial caterpillars exposed in the field were predated. While there was a significant difference in the predation frequency of caterpillar prey between herbivory treatments, our generalised linear mixed model showed a marginal influence on predation risk, but predator type and local landscape showed significant and relatively higher effects. Arthropods were the most significant predators followed by mammals, birds, and reptiles. Furthermore, an increasing proportion of urban developed areas was associated with a decreased risk of predation in artificial caterpillar models. This study implies that regardless of the specific foraging locations chosen by the arthropod prey, predators are likely to prey on available prey in urban and agricultural landscape environments. Our study provides additional evidence that urbanisation can reduce prey-predator interactions. Considering our findings, we suggest that increasing tree cover and green spaces may effectively improve prey-predator interactions in urbanised areas. [ABSTRACT FROM AUTHOR]

Abstract Background Centipedes are terrestrial and predatory arthropods that possess an evolutionary transformed pair of appendages used for venom injection—the forcipules. Many arthropods incorporate reinforcing elements into the cuticle of their piercing or biting structures to enhance hardness, elasticity or resistance to wear and structural failure. Given their frequent exposure to high mechanical stress, we hypothesise that the cuticle of the centipede forcipule might be mechanically reinforced. With a combination of imaging, analytical techniques and mechanical testing, we explore the centipede forcipule in detail to shed light on its morphology and performance. Additionally, we compare these data to characteristics of the locomotory leg to infer evolutionary processes. Results We examined sclerotization patterns using confocal laser-scanning microscopy based on autofluorescence properties of the cuticle (forcipule and leg) and elemental composition by energy-dispersive X-ray spectroscopy in representative species from all five centipede lineages. These experiments revealed gradually increasing sclerotization towards the forcipular tarsungulum and a stronger sclerotization of joints in taxa with condensed podomeres. Depending on the species, calcium, zinc or chlorine are present with a higher concentration towards the distal tarsungulum. Interestingly, these characteristics are more or less mirrored in the locomotory leg’s pretarsal claw in Epimorpha. To understand how incorporated elements affect mechanical properties, we tested resistance to structural failure, hardness (H) and Young’s modulus (E) in two representative species, one with high zinc and one with high calcium content. Both species, however, exhibit similar properties and no differences in mechanical stress the forcipule can withstand. Conclusions Our study reveals similarities in the material composition and properties of the forcipules in centipedes. The forcipules transformed from an elongated leg-like appearance into rigid piercing structures. Our data supports their serial homology to the locomotory leg and that the forcipule’s tarsungulum is a fusion of tarsus and pretarsal claw. Calcium or zinc incorporation leads to comparable mechanical properties like in piercing structures of chelicerates and insects, but the elemental incorporation does not increase H and E in centipedes, suggesting that centipedes followed their own pathways in the evolutionary transformation of piercing tools.

The described dataset contains occurrence records of invertebrate specimens deposited at the State Museum of Natural History of the NAS of Ukraine, Lviv, Ukraine (SMNH NASU). It combines diverse taxonomic groups, mostly belonging to the class Insecta of the phylum Arthropoda, that were selected as prioritised for digitisation in war conditions. Selected specimens were ascertained as those being the most vulnerable to hostilities and requiring virtual preservation. Such virtual preservation is essential in the war realities as collection can be lost or damaged at any moment, resulting in a significant retrospective biodiversity data gap. At the same time, collection virtualisation and its deposition on the internet grant remote access to scientists who cannot visit it in person due to the war. Moreover, we believe that the mobilisation of the data from the Ukrainian collections and their publication online are essential for the integration of Ukrainian research facilities into a global scientific biodiversity pool.A total of 3,660 occurrence records mobilised in 2023-2024 from the collection of invertebrates of the SMNH NASU, were published. This dynamic dataset will be continually supplied by new records during further digitisation work.

Discoveries of new species often depend on one or a few specimens, leading to delays as researchers wait for additional context, sometimes for decades. There is currently little professional incentive for a single expert to publish a stand-alone species description. Additionally, while many journals accept taxonomic descriptions, even specialist journals expect insights beyond the descriptive work itself. The combination of these factors exacerbates the issue that only a small fraction of marine species are known and new discoveries are described at a slow pace, while they face increasing threats from accelerating global change. To tackle this challenge, this first compilation of Ocean Species Discoveries (OSD) presents a new collaborative framework to accelerate the description and naming of marine invertebrate taxa that can be extended across all phyla. Through a mode of publication that can be speedy, taxonomy-focused and generate higher citation rates, OSD aims to create an attractive home for single species descriptions. This Senckenberg Ocean Species Alliance (SOSA) approach emphasises thorough, but compact species descriptions and diagnoses, with supporting illustrations and with molecular data when available. Even basic species descriptions carry key data for distributions and ecological interactions (e.g., host-parasite relationships) besides universally valid species names; these are essential for downstream uses, such as conservation assessments and communicating biodiversity to the broader public.This paper presents thirteen marine invertebrate taxa, comprising one new genus, eleven new species and one re-description and reinstatement, covering wide taxonomic, geographic, bathymetric and ecological ranges. The taxa addressed herein span three phyla (Mollusca, Arthropoda, Echinodermata), five classes, eight orders and twelve families. Apart from the new genus, an updated generic diagnosis is provided for four other genera. The newly-described species of the phylum Mollusca are Placiphorella methanophila Vončina, sp. nov. (Polyplacophora, Mopaliidae), Lepetodrilus marianae Chen, Watanabe & Tsuda, sp. nov. (Gastropoda, Lepetodrilidae), Shinkailepas gigas Chen, Watanabe & Tsuda, sp. nov. (Gastropoda, Phenacolepadidae) and Lyonsiella illaesa Machado & Sigwart, sp. nov. (Bivalvia, Lyonsiellidae). The new taxa of the phylum Arthropoda are all members of the subphylum Crustacea: Lepechinella naces Lörz & Engel, sp. nov. (Amphipoda, Lepechinellidae), Cuniculomaera grata Tandberg & Jażdżewska, gen. et sp. nov. (Amphipoda, Maeridae), Pseudionella pumulaensis Williams & Landschoff, sp. nov. (Isopoda, Bopyridae), Mastigoniscus minimus Wenz, Knauber & Riehl, sp. nov. (Isopoda, Haploniscidae), Macrostylis papandreas Jonannsen, Riehl & Brandt, sp. nov. (Isopoda, Macrostylidae), Austroniscus indobathyasellus Kaiser, Kniesz & Kihara, sp. nov. (Isopoda, Nannoniscidae) and Apseudopsis daria Esquete & Tato, sp. nov. (Tanaidacea, Apseudidae). In the phylum Echinodermata, the reinstated species is Psychropotes buglossa E. Perrier, 1886 (Holothuroidea, Psychropotidae).The study areas span the North and Central Atlantic Ocean, the Indian Ocean and the North, East and West Pacific Ocean and depths from 5.2 m to 7081 m. Specimens of eleven free-living and one parasite species were collected from habitats ranging from an estuary to deep-sea trenches. The species were illustrated with photographs, line drawings, micro-computed tomography, confocal laser scanning microscopy and scanning electron microscopy images. Molecular data are included for nine species and four species include a molecular diagnosis in addition to their morphological diagnosis.The five new geographic and bathymetric distribution records comprise Lepechinella naces Lörz & Engel, sp. nov., Cuniculomaera grata Tandberg & Jażdżewska, sp. nov., Pseudionella pumulaensis Williams & Landschoff, sp. nov., Austroniscus indobathyasellus Kaiser, Kniesz & Kihara, sp. nov. and Psychropotes buglossa E. Perrier, 1886, with the novelty spanning from the species to the family level. The new parasite record is Pseudionella pumulaensis Williams & Landschoff, sp. nov., found in association with the hermit crab Pagurus fraserorum Landschoff & Komai, 2018.

Abstract Background Evolution of novelty is a central theme in evolutionary biology, yet studying the origins of traits with an apparently discontinuous origin remains a major challenge. Venom systems are a well-suited model for the study of this phenomenon because they capture several aspects of novelty across multiple levels of biological complexity. However, while there is some knowledge on the evolution of individual toxins, not much is known about the evolution of venom systems as a whole. One way of shedding light on the evolution of new traits is to investigate less specialised serial homologues, i.e. repeated traits in an organism that share a developmental origin. This approach can be particularly informative in animals with repetitive body segments, such as centipedes. Results Here, we investigate morphological and biochemical aspects of the defensive telopodal glandular organs borne on the posterior legs of venomous stone centipedes (Lithobiomorpha), using a multimethod approach, including behavioural observations, comparative morphology, proteomics, comparative transcriptomics and molecular phylogenetics. We show that the anterior venom system and posterior telopodal defence system are functionally convergent serial homologues, where one (telopodal defence) represents a model for the putative early evolutionary state of the other (venom). Venom glands and telopodal glandular organs appear to have evolved from the same type of epidermal gland (four-cell recto-canal type) and while the telopodal defensive secretion shares a great degree of compositional overlap with centipede venoms in general, these similarities arose predominantly through convergent recruitment of distantly related toxin-like components. Both systems are composed of elements predisposed to functional innovation across levels of biological complexity that range from proteins to glands, demonstrating clear parallels between molecular and morphological traits in the properties that facilitate the evolution of novelty. Conclusions The evolution of the lithobiomorph telopodal defence system provides indirect empirical support for the plausibility of the hypothesised evolutionary origin of the centipede venom system, which occurred through functional innovation and gradual specialisation of existing epidermal glands. Our results thus exemplify how continuous transformation and functional innovation can drive the apparent discontinuous emergence of novelties on higher levels of biological complexity.

The chelicerate body plan is distinguished from other arthropod groups by its division of segments into 2 tagmata: the anterior prosoma ("cephalothorax") and the posterior opisthosoma ("abdomen"). Little is understood about the genetic mechanisms that establish the prosomal-opisthosomal (PO) boundary. To discover these mechanisms, we created high-quality genomic resources for the large-bodied spider Aphonopelma hentzi. We sequenced specific territories along the antero-posterior axis of developing embryos and applied differential gene expression analyses to identify putative regulators of regional identity. After bioinformatic screening for candidate genes that were consistently highly expressed in only 1 tagma (either the prosoma or the opisthosoma), we validated the function of highly ranked candidates in the tractable spider model Parasteatoda tepidariorum. Here, we show that an arthropod homolog of the Iroquois complex of homeobox genes is required for proper formation of the boundary between arachnid tagmata. The function of this homolog had not been previously characterized, because it was lost in the common ancestor of Pancrustacea, precluding its investigation in well-studied insect model organisms. Knockdown of the spider copy of this gene, which we designate as waist-less, in P. tepidariorum resulted in embryos with defects in the PO boundary, incurring discontinuous spider germ bands. We show that waist-less is required for proper specification of the segments that span the prosoma-opisthosoma boundary, which in adult spiders corresponds to the narrowed pedicel. Our results demonstrate the requirement of an ancient, taxon-restricted paralog for the establishment of the tagmatic boundary that defines Chelicerata. The chelicerate body plan is unique among arthropods because segments are divided into two tagmata – cephalothorax and abdomen – but the mechanisms that establish the boundary between them remains unclear. Here, the authors identify a new gene named waist-less that is required for patterning the spider body plan. [ABSTRACT FROM AUTHOR]

Background: Centipedes are terrestrial and predatory arthropods that possess an evolutionary transformed pair of appendages used for venom injection—the forcipules. Many arthropods incorporate reinforcing elements into the cuticle of their piercing or biting structures to enhance hardness, elasticity or resistance to wear and structural failure. Given their frequent exposure to high mechanical stress, we hypothesise that the cuticle of the centipede forcipule might be mechanically reinforced. With a combination of imaging, analytical techniques and mechanical testing, we explore the centipede forcipule in detail to shed light on its morphology and performance. Additionally, we compare these data to characteristics of the locomotory leg to infer evolutionary processes. Results: We examined sclerotization patterns using confocal laser-scanning microscopy based on autofluorescence properties of the cuticle (forcipule and leg) and elemental composition by energy-dispersive X-ray spectroscopy in representative species from all five centipede lineages. These experiments revealed gradually increasing sclerotization towards the forcipular tarsungulum and a stronger sclerotization of joints in taxa with condensed podomeres. Depending on the species, calcium, zinc or chlorine are present with a higher concentration towards the distal tarsungulum. Interestingly, these characteristics are more or less mirrored in the locomotory leg's pretarsal claw in Epimorpha. To understand how incorporated elements affect mechanical properties, we tested resistance to structural failure, hardness (H) and Young's modulus (E) in two representative species, one with high zinc and one with high calcium content. Both species, however, exhibit similar properties and no differences in mechanical stress the forcipule can withstand. Conclusions: Our study reveals similarities in the material composition and properties of the forcipules in centipedes. The forcipules transformed from an elongated leg-like appearance into rigid piercing structures. Our data supports their serial homology to the locomotory leg and that the forcipule's tarsungulum is a fusion of tarsus and pretarsal claw. Calcium or zinc incorporation leads to comparable mechanical properties like in piercing structures of chelicerates and insects, but the elemental incorporation does not increase H and E in centipedes, suggesting that centipedes followed their own pathways in the evolutionary transformation of piercing tools. [ABSTRACT FROM AUTHOR]

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One of the fundamental aims of ecological, epidemiological and evolutionary studies of host–parasite interactions is to unravel which factors affect parasite virulence. Theory predicts that virulence and transmission are correlated by a trade-off, as too much virulence is expected to hamper transmission owing to excessive host damage. Coinfections may affect each of these traits and/or their correlation. Here, we used inbred lines of the spider mite Tetranychus urticae to test how coinfection with T. evansi impacted virulence–transmission relationships at different conspecific densities. The presence of T. evansi on a shared host did not change the relationship between virulence (leaf damage) and the number of transmitting stages (i.e. adult daughters). The relationship between these traits was hump-shaped across densities, both in single and coinfections, which corresponds to a trade-off. Moreover, transmission to adjacent hosts increased in coinfection, but only at low T. urticae densities. Finally, we tested whether virulence and the number of daughters were correlated with measures of transmission to adjacent hosts, in single and coinfections at different conspecific densities. Traits were mostly independent, meaning that interspecific competitors may increase transmission without affecting virulence. Thus, coinfections may impact epidemiology and parasite trait evolution, but not necessarily the virulence–transmission trade-off. This article is part of the theme issue 'Diversity-dependence of dispersal: interspecific interactions determine spatial dynamics'. [ABSTRACT FROM AUTHOR]

Context-dependent dispersal allows organisms to seek and settle in habitats improving their fitness. Despite the importance of species interactions in determining fitness, a quantitative synthesis of how they affect dispersal is lacking. We present a meta-analysis asking (i) whether the interaction experienced and/or perceived by a focal species (detrimental interaction with predators, competitors, parasites or beneficial interaction with resources, hosts, mutualists) affects its dispersal; and (ii) how the species' ecological and biological background affects the direction and strength of this interaction-dependent dispersal. After a systematic search focusing on actively dispersing species, we extracted 397 effect sizes from 118 empirical studies encompassing 221 species pairs; arthropods were best represented, followed by vertebrates, protists and others. Detrimental species interactions increased the focal species' dispersal (adjusted effect: 0.33 [0.06, 0.60]), while beneficial interactions decreased it (−0.55 [−0.92, −0.17]). The effect depended on the dispersal phase, with detrimental interactors having opposite impacts on emigration and transience. Interaction-dependent dispersal was negatively related to species' interaction strength, and depended on the global community composition, with cues of presence having stronger effects than the presence of the interactor and the ecological complexity of the community. Our work demonstrates the importance of interspecific interactions on dispersal plasticity, with consequences for metacommunity dynamics. This article is part of the theme issue 'Diversity-dependence of dispersal: interspecific interactions determine spatial dynamics'. [ABSTRACT FROM AUTHOR]

We assessed the relative importance of environmental filtering and dispersal limitation in structuring foliage- and ground-dwelling arthropod communities in central North Carolina. We hypothesized that differences in both local environment and dispersal distance between sites would predict differences in community composition, but that dispersal distance would be more important for ground arthropods than for foliage arthropods. We used variance partitioning to quantify the relative explanatory power of differences in the local environment and dispersal distance between sampling plots. For foliage arthropods, the full set of predictors explained 37–39% of the variance in community dissimilarity, while the full set of predictors explained 42–56% of the variance for ground arthropods. Environmental predictors alone consistently explained more variance in community dissimilarity than geographic predictors alone for ground arthropods, but the variance explained by each predictor set alone varied for foliage arthropods depending on the metric of community dissimilarity. Examining communities of multiple arthropod groups across the same spatial gradient highlights the scale-dependence of these processes and illustrates how variation in the environment can alter the relative abundance of specialist and generalist taxa. [ABSTRACT FROM AUTHOR]

Direct trophic links between aboveground and belowground animal communities are rarely considered in food web models. Most invertebrate animals inhabiting aboveground space eventually become prey of soil predators and scavengers forming a gravity-driven spatial subsidy to detrital food webs, but its importance remains unquantified. We used laboratory-grown 15N-labeled Collembola to trace the incorporation of arthropod rain into soil food webs. Live or euthanized Collembola were supplemented once to field mesocosms in the amount equivalent to the mean daily input of the arthropod rain (19 mg d.w. m−2). After the addition of live Collembola, the isotopic label was found most often in predatory Trombidiformes (83% of samples) and Mesostigmata mites (85%), followed by Araneae (58%), Chilopoda (45%), and Coleoptera (29%). Among non-predatory groups, the isotopic label was recorded in Thysanoptera (27%), Collembola (24%), and Oribatida (18%). The 15N-label was also detected in Symphyla, Formicidae, Diplura, Diplopoda, Opiliones, Diptera, Hemiptera, Oligochaeta, and Nematoda. There was a positive correlation between natural 15N abundance and the frequency of the isotopic label among predators, but not among decomposers. In the non-replicated treatment, in which dead collembolans were added, the label was found in predators and decomposers in approximately equal proportions (21–25%). Unlike other forms of the aboveground subsidy (such as leaf litter, frass, or honeydew) that are primarily processed by microorganisms, arthropod rain is assimilated directly by the animals. The high frequency of consumption of the aboveground subsidy suggests that it plays a significant role in maintaining the abundance of soil predators. [ABSTRACT FROM AUTHOR]

The data on host–arthropod associations between arthropods and Passalidae are summarised. In the family Diarthrophallidae, the new genus Hamptonilla is established to replace the junior homonym Lombardiniella Womersley, 1961. A total of 404 arthropod species (including those collected from unidentified Passalidae) have been found on 170 species of Passalidae (including those determined as aff.). On Passalidae, arthropods have been found belonging to Astigmata (79 species), Diptera (1), Ixodida (1), Mesostigmata (242), Oribatida (27), Pseudoscorpiones (25) and Trombidiformes (29). Among Mesostigmata, the most species were found in Diarthrophallidae (63), Diplogyniidae (37), Klinckowstroemiidae (36), Fedrizziidae (33) and Megisthanidae (15), among Astigmata in Canestriniidae (68) and among Trombidiformes in Heterocheylidae (26). The largest number of arthropod species were collected from Odontotaenius zodiacus (36), O. striatopunctatus (23), Passalus punctiger (22), O. disjunctus (20), Mastachilus australasicus (17), P. interstitialis (17), Pharochilus dilatatus (14), P. interruptus (13) and Aceraius grandis (11). Arthropods are recorded from 170 species of Passalidae. The least host-specific species are: Tridenchthonius mexicanus (found on 25 species of passalids), Lustrochernes aff. reimoseri (21), Americhernes aff. incertus (12) and L. intermedius (12). The relationships between arthropods and Passalidae are best known in Central America (114 arthropod species from 58 species of Passalidae). In Asia (102 from 32), Oceania (77 from 31), South America (64 from 38), Africa (38 from 13) and North America (20 from 2). Among countries the best studied are Mexico, Brazil, Australia, Indonesia, Philippines, Papua New Guinea and Costa Rica. [ABSTRACT FROM AUTHOR]

The sub-Antarctic terrestrial ecosystems survive on isolated oceanic islands in the path of circumpolar currents and winds that have raged for more than 30 million years and are shaped by climatic cycles that surpass the tolerance limits of many species. Surprisingly little is known about how these ecosystems assembled their native terrestrial fauna and how such processes have changed over time. Here, we demonstrate the patterns and timing of colonization and speciation in the largest and dominant arthropod predators in the eastern sub-Antarctic: spiders of the genus Myro. Our results indicate that this lineage originated from Australia before the Plio-Pleistocenic glacial cycles and underwent an adaptive radiation on the Crozet archipelago, from where one native species colonized multiple remote archipelagos via the Antarctic circumpolar current across thousands of kilometers. The results indicate limited natural connectivity between terrestrial macroinvertebrate faunas in the eastern sub-Antarctic and partial survival of repeated glaciations in the Plio-Pleistocene. Furthermore, our findings highlight that by integrating arthropod taxa from multiple continents, the climatically more stable volcanic Crozet archipelago played a critical role in the evolution and distribution of arthropod life in the sub-Antarctic. [ABSTRACT FROM AUTHOR]

Vast grassland areas disappear due to abandonment, conversion to arable fields or urban areas. Consequently, grassland species have declined dramatically during and since the last century. The majority of remaining European grasslands are managed, many of them by mowing, which, in general, decreases arthropods' abundance and species richness.Here, we aimed to study the effects of width and proportion of refuge areas on local abundance and richness of arthropods in hay meadows. Within a ca. 4000 ha semi‐natural grassland area of the Great Hungarian Plain, we established refuge strips of different widths (3 and 9 m) and proportion of total field area (10 and 25%) following a randomised block design with six replicates per treatment. We studied five arthropod groups (grasshoppers, true bugs, carabids and ground‐dwelling and vegetation‐dwelling spiders), which we sampled 2 weeks after mowing by sweep netting and pitfall traps.Uncut strips were warmer and moister than the mown areas. The effects of refuge strips and their arrangement were stronger on the vegetation‐dwelling than on ground‐dwelling arthropods, although all taxa were affected in some way. We found more true bugs in mown areas between narrow strips than between wide strips. The interaction effect of width and proportion of refuge strips on the abundance of grasshoppers, ground‐dwelling spiders and species richness of carabids showed that wider strips are more beneficial if their proportion is low and narrow strips are more beneficial with high proportion.Synthesis and applications: Our findings provide evidence that uncut refuge strips can harbour diverse and abundant arthropod assemblages in hay meadows and mitigate the adverse effects of uniformly executed mowing on arthropods. Modifying attributes and considering farming practices, wide strips with a low (10%) proportion of total field area seem optimal for both conservation and practitioners. [ABSTRACT FROM AUTHOR]

An updated phylogenomic tree of the Nudiviridae is presented, including 49 species, proposing two genera associated with ectoparasitic insects. Evolution of the family Nudiviridae is estimated to have occurred in the mid-Devonian, matching the timeline of the insect's evolution. All the crustacean-infecting nudiviruses have likely emerged from a single common ancestor (~143 million years ago), perhaps transmitted to Jurassic crustaceans by an insect host. The Nudiviridae have a proclivity for ectoparasitic arthropods (i.e., lice and fleas), linked to multiple diversification events in the Triassic (early Betanudivirinae split), Jurassic (involving ectoparasitic hosts of alphanudiviruses), and Cretaceous periods (Zeta/Etanudivirus diversification). Nudiviruses inhabit various geographical and climatic zones, including members from subpolar habitats. The nudiviruses (family: Nudiviridae) are large double-stranded DNA (dsDNA) viruses that infect insects and crustaceans, and have most recently been identified from ectoparasitic members (fleas and lice). This virus family was created in 2014 and has since been expanded via the discovery of multiple novel viral candidates or accepted members, sparking the need for a new taxonomic and evolutionary overview. Using current information (including data from public databases), we construct a new comprehensive phylogeny, encompassing 49 different nudiviruses. We use this novel phylogeny to propose a new taxonomic structure of the Nudiviridae by suggesting two new viral genera (Zetanudivirus and Etanudivirus), from ectoparasitic lice. We detail novel emerging relationships between nudiviruses and their hosts, considering their evolutionary history and ecological role. [ABSTRACT FROM AUTHOR]